1856.] Report of the Magnetic Survey of India. 115 



in valleys of 12,500 to 14,000 E. E. elevation, the ripening of grain 

 (a sort of wheat) takes place at a considerably earlier period than 

 in the valleys of the Himalayas which are situated only at heights 

 of from 10,000 to 11,500 E. E. ; the principal cause of this appears 

 to be that, in the higher Himalayan Mountains, the great amount 

 of snow retards vegetation in the spring, and tends after melting to 

 cool down the temperature of the surface of the ground for some 

 considerable time, whilst in Thibet the fall of snow in winter is 

 never large, and, as we have been informed, it constantly melts away 

 again some days after its fall. 



Influence of height upon Man. 

 10th. The influence of height upon the constitution of man 

 varies exceedingly in different individuals. It depends much on the 

 physical strength, and the acclimatization of a few days at great 

 elevations certainly tends very considerably to diminish its effects ; 

 but there is no doubt that this influence exists ; it generally pro- 

 duces more or less severe headache, and difficulty of respiration, 

 and in some instances we saw that some of our people were spitting 

 blood ; complaints of the eyes too are of frequent occurrence, pro- 

 duced in part by the bright light of the snow, in part by heavy winds 

 which blow small dust into the eyes. It certainly is difficult to 

 ascertain how much is due in these phenomena to the diminished 

 pressure of the atmosphere, and how much to the great bodily 

 exertion. 



We had occasion ourselves to test the great effect of acclima- 

 tization ; when for the first time we crossed heights of 17,500 and 

 18,000 E. E. we felt more or less headache, but after having crossed 

 several others of these passes, and slept and lived on them for some 

 days, we found ourselves quite free from any complaints at heights 

 of 18,000 and 19,000 E. E., when, however, we ascended Ibi Gamin 

 to a height of more than 22,000 E. E. neither we nor any one ot 

 our people escaped headache, difficulty of breathing and severe 

 pains in the eyes. 



Geography and Geology. 

 11th. We had with us two Theodolites, a large one minutely 

 divided by Pistor, at Berlin, and a smaller one by Jones, which have 

 remained in perfect order during the whole of the journey. 



Q 2 



